for rear discs your concern should mainly be condition and spacing. In particular some lenticular discs have clearance issues with narrow chainstay bikes (Cervelo T4, etc) but in regards to Corima's precisely, they have made them for a long time and so you'll see more around (of vastly differing ages) Do your research on the specific ones you find that interest you, most big brands are fairly easy to research.
There is official data on 3-5 spokes... but I'm not sure it's ever been made public, (I think Bassett did a study, and Zipp/Hed at one point) there is plenty of independent comparison out there though. In general, a good 3 spoke (Hed3 specifically) is about as aero as you can buy, with the correct profile tyre fit to it. It is aerodynamically generally superior to 4-5 spokes. However, 5 spokes are considerably stiffer than 3 spokes and have the benefit of looking sweet. In general for track the older, narrow 19mm designed rim is pretty hard to beat with a 19mm tyre glued to it. (Both H3's and Mavic iO's) more modern designed wheels are generally built around wider rims, which becomes more useful the worse the track surface you're riding on (I wouldn't want to be riding 19mm vitt pista speeds at Dick Lane or some other beat up old outdoor 'drome for instance) There are plenty of other spoked wheel designs out there of varying quality.
In general when looking at/for wheel data online that specific to track... you can look at road/triathlon wheel shootouts/comparisons, and in particular look at the lower (closer to 0) yaw angles when determining. Indoors yaw will be close to 0, outdoors wind is a factor but at general track speeds it will still be considerably lower than what someone on the road would experience.
In short, imo when looking for wheels
- If you're a
Sprinter, Stiffness > Aero - Handling
Pursuiter, Aero > Stiffness > Handling
All arounder (bunchie races) Handling > Aero > Stiffness
All with an optimal, low crr tyre of course